Estimated Effects on Water
Quality of Lake Houston From Interbasin Transfer of Water From the Trinity River,
Texas

By Fred Liscum and Jeffery W. East

U.S. Geological Survey
Water-Resources Investigations Report 00–4082

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Volume-weighted daily means computed for observed and simulated data for
selected properties and constituents at segments 19 and 32 during calibration
and test years

5.

Summary of reliability index computed for selected properties and constituents
at segments 19 and 32 during calibration and test years

6.

Summary of compatibility index for volume-weighted daily mean properties
and constituents simulated for base dataset and for six water-transfer scenarios
at segment 32 in Lake Houston, during selected simulation periods

7.

Summary of percent change between volume-weighted mean properties and
constituents simulated for base dataset and for six water-transfer scenarios
at segment 32 in Lake Houston, 1985–90

Abstract

The City of Houston is considering the transfer of water from the Trinity River
to Lake Houston (on the San Jacinto River) to alleviate concerns about adequate
water supplies for future water demands. The U.S. Geological Survey, in cooperation
with the City of Houston, conducted a study to estimate the effects on the water
quality of Lake Houston from the transfer of Trinity River water.

A water-quality model, CE–QUAL–W2, was used to simulate six water-quality
properties and constituents for scenarios of interbasin transfer of Trinity
River water. Three scenarios involved the transferred Trinity River water augmenting
streamflow in the East Fork of Lake Houston, and three scenarios involved the
transferred water replacing streamflow from the West Fork of the San Jacinto
River.

The estimated effects on Lake Houston were determined by comparing volume-weighted
daily mean water temperature, phosphorus, ammonia nitrogen, nitrite plus nitrate
nitrogen, algal biomass, and dissolved oxygen simulated for each of the transfer
scenarios to simulations for a base dataset. The effects of the interbasin transfer
on Lake Houston do not appear to be detrimental to water temperature, ammonia
nitrogen, or dissolved oxygen. Phosphorus and nitrite plus nitrate nitrogen
showed fairly large changes when Trinity River water was transferred to replace
West Fork San Jacinto River streamflow. Algal biomass showed large decreases
when Trinity River water was transferred to augment East Fork Lake Houston streamflow
and large increases when Trinity River water was transferred to replace West
Fork San Jacinto River streamflow. Regardless of the scenario simulated, the
model indicated that light was the limiting factor for algal biomass growth.